A new poll released Friday finds that more than two-thirds of Americans oppose U.S. military action in Syria to help end the civil war between the Bashar al-Assad regime and rebel forces that has killed more than 70,000 people.

The most recent Gallup survey found that 68 percent of American adults oppose U.S. military action in Syria, even if diplomatic and economic efforts fail to end the 26-month-long conflict. Twenty-four percent say they would support military involvement.

However, the poll of 1,011 adults, conducted May 28-29, also found that 58 percent of respondents are not optimistic that diplomatic efforts will succeed. Only 27 percent of those surveyed said they still believe such efforts can be successful.

Sen. John McCain of Arizona visited with rebel fighters in Syria recently and said he supports the United States providing arms to the rebels. But so far, the Obama administration has approached the rebels with caution and has limited its involvement to third-party peace talks and providing food and medical aid to various anti-Assad groups that are trying to end his family's long dictatorship.

A new poll released Friday finds that more than two-thirds of Americans oppose U.S. military action in Syria to help end the civil war between the Bashar al-Assad regime and rebel forces that has killed more than 70,000 people.